Pliers



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j7-ATTORNEY.

July 27, 1937. l E. L; AIKEN l Filed Nov. 18, 1936 Patented July 27,1937 UNET STATES man PLIERS Application November 18, 1936, Serial No.111,377

2 Claims.

My invention pertains to hand tools and relates more particularly tothat kind of such tools as are known as pliers.

Pliers as universally made employ two types of pivot joints. That morefrequently used is known as the lap joint and the other seldom used nowis known as the box joint. Both of these joints have a serious defect inthat not more than fifty percent of the cross-sectional area of at leastone of the jaws is available to resist the strain put upon the plier inuse. This defect, while prejudicial in any type of pliers, is aggravatedin side cutting pliers of the lap joint type as the cutting edgeoverhangs to a maximum extent the unsupported portion of one jaw. Thuswhen such pliers are used in cutting a torsional stress is added whichgreatly increases the probability of fracture of such jaw. This isproven by the fact that fractured jaws in pliers almost invariably occurin the jaw containing the overhanging cutting edge. Further, in bothtypes of joints, a relatively small diameter pivot pin is utilized,which is usually riveted in place. Such pliers almost invariably bindwhen opened to their full extent and in fact when new and until they aregiven considerable use can very seldom be opened to their full extent,thus decreasing the eifectiveness of the pliers.

-One of the principal objects of my invention is to produce a pliershaving a more eective and efficient pivoting means.

Another object comprises producing a pliers l in which the possibilityof breakage of the jaws at or near the pivot point is substantiallyeliminated.

A further object comprises producing a pliers in which the bearing areasat the point of pivot are greatly increased to reduce wear, resultantlooseness and to eliminate binding.

A still further object comprises producing a pliers in which the ratioof leverage ongopposite sides of the pivot point is increased to reducethe expenditure of energy by the operator to accomplish the sameeffective cutting or gripping.

I achieve all of the above noted desirable features and others whichwill hereinafter be apparent by means of the combination of the novelstructures described in the following speciiica tion with reference tothe accompanying drawing forming a part thereof.

In the drawing, in which like reference numerals designate correspondingparts:

Fig. 1 is a side plan View of my improved pliers with portions of thehandles and one of the ring lock Washers broken away.

(Cl. 81--5l) Fig. 2 is a top plan View of the same with a portion of oneof the jaws and the handles broken away.

Fig. 3 is a view of the jaw portion of one of the lever members with thehandle portion 5 broken away and the pivoting means partially sectioned.

Fig. 4 is a broken perspective view of the common lap joint side cuttingpliers.

Fig. 5 is a partially broken view of the jaw portion of one of the levermembers showing an internal arrangement of the pivoting means partiallyin section.

Referring now particularly to Figs. 1-3, inclusive, in which I haveshown my invention as embodiedv in a side cutting pliers merely by wayof example, two lever members each comprising a jaw portion i and handleportion 3 and jaw portion 2 and handle portion il, respectively, areprovided in the jaw portions with serrated grip portions as shown inFig. 3 and cutting edges it. Each of the lever members are, as shown inFig. 1, formed so that the handles overlap at a point between the pivotpoint and the handle portion of the lever. The levers are flattened 25at this portion so that the handle portions and jaw portions when thelevers are operatively articulated may be coplanar, as clearly shown iiiFig. 2.

There are provided, as shown in Figs. l and 30 3, in each of the levermembers, recesses forming shoulder portions 8 and channel portions 9.These recesses, forming arcuate shoulders and grooves or channels are sopositioned in each of the members that when the members are placed asshown in Fig. 1 the arcuate shoulders and channels in one member becomecoplanar and coaxial with those in the other member to present almostcompletely annular shoulders and channels. Radial portions l2 and i3 arecut away in each of the members, respectively, to permit the pliers tobe opened for use.

With the lever members in the position shown in Fig. l, a pair of whatmay be called ring lock washers 5 and il, formed with annular tonguesand channels adapted to mesh with the grooves 9 and shoulders 8 formedby the recesses in the jaws 2 and I are inserted and are held inposition pivotally articulating the lever members by means of the stud lwhich is internally threaded to receive a clamping screw i5. The stud 'ipasses through a clearance aperture provided by substantiallysemi-circular` openings in each of the jaw members I and 2 as shown inFig. 3.

In operation the ring lock washers 5 and ll cooperating with theshoulders and grooves provided in the jaw portions l and 2 function aspivoting means operatively articulating the lever members. It will benoted in Fig. 3 that preferably the central shoulders are cut away toensure that the bearing between the washers 5 and l l and the levermembers takes place on the circumferences of the shoulders of thesewashers in contact with the corresponding circumferences and bottoms ofthe grooves 9 provided in the jaw portions I and 2. The pvot area isthus greatly increased over that now provided by a single pivot pin toensure that the pliers will not bind and that wear is reduced toeliminate looseness. Further, it will be noticed on reference to Fig. 4which shows a side cutting pliers as now made with the usual lap joint,that the cutting edge 3Q in the jaw portion 29 overhangs by nity percentthe solid cross-sectional area of the jaw 29. In the construction shownin Fig. 3, the cutting edge l0 overhangs the solid material of the jawby only part of the depth of the arcuate grooves 9 and this can bereadily seen to be very considerably less than fty percent of thecross-sectional area of the jaw. Thus, in my improved pliers, thetorsional strain added to the compression strain when the pliers is usedis very considerably reduced, thus reducing the tendency of the jaw tofracture.

The ring lock washers 5 and il may be combined into one washer 2i, asshown in Fig. 5, and the meshing arcuate shoulders and grooves in thejaw member 22 may be made in each jaw on the internal faces of the jawsto operatively articulate the lever members, and such articulation maybe maintained as hitherto explained by means of the stud 21 and screw23.

The lever members are or" course made in the usual manner from anysuitable material such as tool steel and the washers 5 and i i, Fig. 3,or 2i, Fig. 5, may be likewise made of tool steel and if desiredhardened for maximum resistance to wear.

It will be apparent from the foregoing that as the radius of thepivoting area is increased there will be less possibility of bindingcaused by twisting of the pliers in use and I have further found inpliers made in accordance with my invention that even when the pliersare new and before given any use they may be open to their full extentwithout binding. Because of the fact that with my pivot construction thecutting edge in the case of side cutting pliers can be located closer tothe pivoting point than in the case of the usual lap joint or box jointpliers, the ratio of leverage on either side of the pivot point isincreased so that the expenditure of energy by the operator toaccomplish the same effective cutting or gripping act is reduced.

In test demonstrations which I have made, I have found that suchreduction amounts to approximately seventy percent. Utilizing a standardtesting machine the following cutting resultsv were obtained:

In all cases the pressure on the handles was put at the same distancefrom the pivot point:

Cutting 1/8 steel rod: Ordinary type 81/2 pliers required 135 lbs.pressure-8%" pliers made in accordance with my invention, lbs. pressure.

Cutting insulated copper wire, diameter of wire .229", diameter overinsulation .4z Ordinary 8%2 pliers 230 lbs. pressure-with my improved81/2 pliers, 165 lbs.

It will be apparent from the foregoing that my invention provides apliers having a more eiective and efiicient pivoting means; a pliers inwhich the possibility of breakage of the jaws at or near the pivot pointis substantially eliminated; a pivoting means for pliers in which thebearing area at the pivot point is greatly increased to reduce wear,resultant looseness and to eliminate binding; and a pliers in which theratio of leverage on opposite sides of the pivot point is increased sothat the expenditure of energy by the operator is reduced to accomplishthe same effective cutting or gripping act.

While I have for purposes of illustration disclosed and described myinvention as embodied in a side cutting pliers, it will be obvious thatit may be utilized to advantage with any type of pliers and thatnumerous changes may be made therein without departing from the spiritand scope of the invention as deiined in the claims. Having thuscompletely described my invention, what I claim is new and desire tosecure by United tates Letters Patent is:

l. A hand tool comprising two lever members, each comprising a jaw and ahandle, arcuate recesses in each of said members, said recesses beinglocated between the grip portions of said jaws and said handles, therecesses in one of said members being coplanar with corresponding rencesses in the other of said members when said members are operativelyarticulated, pivot bearing means forming with said coplanar arcuaterecesses annular tongue and groove operative articulation for saidmembers, and means for maintaining such operative articuiation of saidmembers.

2. A pair of pliers comprising, two lever members each comprising a jawand a handle, arcuate recesses in each of said members, said recessesbeing located between the grip portions of said jaws and said handles,said recesses in one of said members being coplanar with correspondingrecesses in the other of said members when said members are operativelyarticulated, a pair of ring lock pivoting washers forming with saidcoplanar arcuate recesses annular tongue and groove operativearticulation for said members and means passing through said washers formaintaining the operative articulation of said members.

EDWARD L. AIKEN.

CFI

